摘要目的 观察氟对体外培养软骨细胞中凋亡相关因子bcl-2和Bax蛋白表达的影响,探讨氟在致软骨细胞凋亡中的作用机制.方法 采用软骨细胞体外培养方法,原代培养乳鼠关节软骨细胞,传第3代后按染氟剂量不同分为0(对照)、5、20、40mg/L组,培养10 d后,透射电镜下观察软骨细胞的超微结构改变,采用Western印迹法检测软骨细胞bcl-2和Bax蛋白表达.结果 透射电镜下,对照组和5 mg/L组软骨细胞呈球形,粗面内质网发达,线粒体膜性结构完整;20、40 mg/L组软骨细胞内可见脂滴增多,胞质内出现大量空泡类物质,细胞内膜结构不清,部分细胞出现核固缩.20、40 mg/L组软骨细胞bcl-2蛋白表达(0.626±0.042、0.531±0.039)较对照组(0.876±0.035)明显降低(P均＜0.01);而Bax蛋白表达(0.966±0.047、1.289±0.156)较对照组(0.642±0.050)明显增加(P均＜0.01).5 mg/L组软骨细胞bcl-2、Bax蛋白表达(0.885±0.065、0.657±0.045)与对照组比较,差异无统计学意义(P均＞0.05).此外,40 mg/L组与20 mg/L组比较,bcl-2、Bax蛋白表达差异有统计学意义(P均＜0.01).结论 染氟20、40 mg/L可对软骨细胞超微结构造成损伤,其通过减少抑凋亡因子bcl-2的表达和增加促凋亡因子Bax的表达,从而产生促进软骨细胞凋亡的作用.

abstractsObjective To study the effect of fluoride on the expression of bcl-2 and Bax in chondrocyte in vitro, and investigate the mechanism of action of chondrocyte apoptosis induced by fluoride. Methods Articular chondrocytes of neonate rat were cultured in vitro and treated with 0(control),5,20,40 mg/L of fluoride,respectively, for 10 days. Then observed the u]trastructure of chondrocytes under eletronicmicroscope, and tested the expression of bcl-2 and Bax in chondrocyte in different groups by Western blotting. Results Abundant rough endoplasmic reticulums (RERs) and complete structure of mitochondria membranes were presented in globular chondrocytes in the control group and 5 mg/L group; but more lipid droplets and vacuoles were seen in the cytoplasm, and the structure of intracellular membranes became incomplete, and some shrieked chromatin and pyknosis were seen in the chondrocytes of the 20,40 mg/L groups. The expression of bcl-2 markedly decreased in 20 mg/L group(0.626 ± 0.042) and 40 mg/L group(0.531± 0.039) compared to the control group(0.876 ± 0.035,all P ＜ 0.01 ). And the expression of Bax significantly increased in 20 mg/L group(0.966 ± 0.047) and 40 mg/Lgroup ( 1 .289 ± 0.156) compared to the control group(0.642 ± 0.050, all P ＜ 0.01). But there was no statistical significant difference of the expression of bcl-2 or Bax between 5 mg/L group(0.885 ± 0.065,0.657 ± 0.045) and control group (all P ＞ 0.05 ). However there were statistical differences of expressions of bcl-2 and Bax between 20 and 40 mg/L groups(all P ＜ 0.01 ). Conclusions Twenty and 40 mg/L fluoride can cause damage to the ultrastructure of chondrocyte, and fluoride possibly promotes chondrocyte apoptosis by reducing the expression of antiapoptotic factor bcl-2 and increasing the expression of Bax.